Therefore, these results showed that, in the population of metastatic KIT exon 11 mutated patients treated with first-line imatinib, the absence of KIT exon 11 deletions or delins 557/558, the female gender, a primitive tumor diameter ≤ 5 cm and polymorphonuclear leucocytosis > 7.5 × 109/L were significant independent prognostic factors for longer PFS, while the performance status was the only significant prognostic factor for OS. This evidence concerns the gene KIT and neoplasm.